Renesas 74FCT244CTQG8

Overview

74FCT244CTQG8 from Renesas Electronics (formerly IDT) is a fast CMOS octal buffer/line driver with 3-state outputs, designed for memory and address bus driving, clock distribution, and bidirectional bus interfacing in industrial systems. It features true TTL input/output compatibility (VOH = 3.3 V typ., VOL = 0.3 V typ.), high drive capability (–15 mA IOH, 64 mA IOL), and operates across –40°C to +85°C at 5.0 V ±5%.

For engineers reviewing the 74FCT244CTQG8 datasheet, 74FCT244CTQG8 pinout, 74FCT244CTQG8 application, or 74FCT244CTQG8 equivalent, key selection criteria include output enable timing (tPZH ≤ 6.5 ns, tPHZ ≤ 5.7 ns), low leakage (≤1 µA max), JEDEC 18 compliance, and TSSOP-20 package suitability for high-density PCB layouts.

Technical Context

The 74FCT244CTQG8 implements dual-rail CMOS logic with TTL-compatible input thresholds (VIH ≥ 2.0 V, VIL ≤ 0.8 V) and rail-to-rail output swing under load. Its two independent 4-bit groups (OEA/OEB control) support asymmetric bus buffering - one group can drive while the other remains in high-impedance state without contention.

It meets MIL-STD-883 Class B requirements for military-grade reliability and supports live insertion via power-off disable outputs. The device uses advanced dual-metal CMOS process to achieve propagation delays as low as 4.1 ns (tPLH/tPHL) at industrial temperature range with CL = 50 pF and RL = 500 Ω.

Key Specifications

Pinout & Package

74FCT244CTQG8 is packaged in a 20-pin Thin Shrink Small Outline Package (TSSOP), measuring 6.5 mm × 4.4 mm × 1.2 mm, with 0.65 mm lead pitch and exposed pad for thermal enhancement.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar octal buffer applications.

Compared with SN74FCT244ATPWR and 74LCX244MTCX, the 74FCT244CTQG8 offers optimal balance of 5 V TTL compatibility, industrial temperature rating, and proven reliability in legacy infrastructure - making it ideal for drop-in upgrades and long-lifecycle industrial deployments.

Availability

74FCT244CTQG8 is available at Aetrix Electronics and suitable for industrial PLCs, test instrumentation, legacy memory subsystems, and embedded control systems requiring stable component supply across extended product lifecycles.

Supply support for 74FCT244CTQG8 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Renesas Electronics Corporation is a global semiconductor leader delivering microcontrollers, analog, power, and connectivity solutions for automotive, industrial, infrastructure, and IoT applications.

The 74FCT244CTQG8 belongs to Renesas' legacy IDT fast CMOS logic family, engineered specifically for high-reliability industrial and military-grade bus interfacing with strict timing, drive, and environmental robustness requirements.

FAQ

What is the maximum operating frequency supported by the 74FCT244CTQG8?

The 74FCT244CTQG8 does not specify a maximum clock frequency in its datasheet because it is an asynchronous buffer - its usable frequency depends on propagation delay and load. With tPLH/tPHL ≤ 4.1 ns and CL = 50 pF, it reliably supports data/address bus toggling up to ≈100 MHz in well-terminated systems. System-level timing must account for board trace delays and fanout capacitance when determining actual maximum toggle rate for the 74FCT244CTQG8.

Is the 74FCT244CTQG8 pin-compatible with the 74FCT244ATQG8?

Yes, the 74FCT244CTQG8 is fully pin-compatible with the 74FCT244ATQG8 - both use identical TSSOP-20 packaging and share the same pinout, function table, and DC/AC electrical specifications. The primary difference lies in timing performance: the 'C' grade guarantees tPLH/tPHL ≤ 4.1 ns (vs. ≤ 4.8 ns for 'A'), and tPZH/tPHZ ≤ 6.5 ns (vs. ≤ 6.2 ns). This makes the 74FCT244CTQG8 suitable for timing-critical upgrades without PCB changes.

Does the 74FCT244CTQG8 support mixed-voltage operation (e.g., 3.3 V inputs with 5 V VCC)?

No, the 74FCT244CTQG8 is not designed for mixed-voltage operation. Its inputs are TTL-compatible (VIH ≥ 2.0 V, VIL ≤ 0.8 V) and tolerate up to VCC + 0.5 V, but applying 3.3 V logic signals directly to inputs while VCC = 5 V is acceptable and within specification. However, driving 3.3 V-only devices from its 5 V outputs requires external level-shifting, as the 74FCT244CTQG8 outputs swing rail-to-rail and exceed 3.3 V absolute maximum ratings of many low-voltage ICs.

What is the recommended decoupling for the 74FCT244CTQG8?

Renesas recommends a minimum 0.1 µF X7R ceramic capacitor placed as close as possible to the VCC pin (pin 20) and GND pin (pin 10) of the 74FCT244CTQG8. For systems with high-output switching activity (e.g., full-bus toggling), adding a second 4.7 µF tantalum or polymer capacitor within 1 inch further stabilizes supply rail droop. Ground plane integrity beneath the TSSOP-20 footprint is critical - avoid splits or narrow traces under the 74FCT244CTQG8 body to minimize inductance and ensure clean return paths.

Can the 74FCT244CTQG8 be used as a level translator between 5 V and 3.3 V logic domains?

The 74FCT244CTQG8 is not a bidirectional level translator. While its TTL-compatible inputs accept 3.3 V logic highs safely (VIH min = 2.0 V), its outputs swing to 5 V levels - directly connecting them to 3.3 V-only inputs risks overvoltage damage. To translate 5 V → 3.3 V, external series resistors or dedicated translators like TXB0108 are required. The 74FCT244CTQG8 functions correctly only as a 5 V domain buffer; use it in 3.3 V systems only with verified 5 V-tolerant receivers.